Trend Analysis of Las Vegas Land Cover and Temperature Using Remote Sensing

The Las Vegas urban area expanded rapidly during the last two decades. In order to understand the impacts on the environment, it is imperative that the rate and type of urban expansion is determined. Remote sensing is an efficient and effective way to study spatial change in urban areas and Spectral Mixture Analysis (SMA) is a valuable technique to retrieve subpixel landcover information from remote sensing images. In this research, urban growth trends in Las Vegas are studied over the 1990 to 2010 period using images from Landsat 5 Thematic Mapper (TM) and National Agricultural Imagery Program (NAIP). The SMA model of TM pixels is calibrated using high resolution NAIP classified image. The trends of land cover change are related to the land surface temperature trends derived from TM thermal infrared images. The results show that the rate of change of various land covers followed a linear trend in Las Vegas. The largest increase occurred in residential buildings followed by roads and commercial buildings. Some increase in vegetation cover in the form of tree cover and open spaces (grass) is also seen and there is a gradual decrease in barren land and bladed ground. Trend analysis of temperature shows a reduction over the new development areas with increased vegetation cover especially, in the form of golf courses and parks. This research provides a useful insight about the role of vegetation in ameliorating temperature rise in arid urban areas

Analysis of Self-Reported Walking for Transit in a Sprawling Urban Metropolitan Area in the Western U.S.

Walkability is associated with increased levels of physical activity and improved health and sustainability. The sprawling design of many metropolitan areas of the western U.S., such as Las Vegas, influences their walkability. The purpose of this study was to consider sprawl characteristics along with well-known correlates of walkability to determine what factors influence self-reported minutes of active transportation. Residents from four neighborhoods in the Las Vegas Metropolitan Area, targeted for their high and low walkability scores, were surveyed for their perceptions of street-connectivity, residential-density, land-use mix, and retail–floor-area ratio and sprawl characteristics including distance between crosswalks, single-entry-communities, high-speed streets, shade, and access to transit. A Poisson model provided the best estimates for minutes of active transportation and explained 11.28% of the variance. The model that included sprawl characteristics resulted in a better estimate of minutes of active transportation compared to the model without them. The results indicate that increasing walkability in urban areas such as Las Vegas requires an explicit consideration of its sprawl characteristics. Not taking such design characteristics into account may result in the underestimation of the influence of sprawl on active transportation and may result in a missed opportunity to increase walking. Understanding the correlates of walkability at the local level is important in successfully promoting walking as a means to increase active transportation and improve community health and sustainability

Potential Fossil Yield Classification (PFYC) Survey of Nevada Surficial Geology, and a Multi-Sensor, Remote Sensing, Change-Detection Study of Land-Use/Land-Cover Urbanization Impacting the Las Vegas Formation Located in Northwestern Las Vegas Valley

This thesis is a combination of two separate but related projects. The first project is a Potential Fossil Yield Classification (PYFC) survey. The PFYC is a Bureau of Land Management funded survey designed to synthesize paleontologic information into a geographic information system (GIS) as a distributable geodatabase. The database is designed to represent surficial geologic deposits contained in a polygon shapefile. Throughout the State of Nevada each polygon represents a mapped geologic unit at a scale of at least 1:250 k. Each mapped geologic unit is then assigned a “potential fossil yield classification”, a numerical ranking value of 1-5 based on the known fossils within a geologic unit. Fossil type and abundance are considered in the assignment of a PFYC value, 1 being the lowest, and 5 being the highest. The second project consists of a multi-temporal land-use/land-cover change detection analysis designed to measure effects of rapid urbanization within a geologic unit identified to have the highest fossil potential based on the results of the PFYC survey. The Las Vegas Formation (LVfm) is a Pleistocene groundwater discharge deposit that has been shown to contain significant vertebrate fossils, thus being assigned a PFYC value of 5. The proximity of the LVfm to the densely populated city of Las Vegas provides a unique opportunity quantify effects of urbanization to lands rich with fossil resources. This project is designed to utilize remotely sensed imagery and aerial light detection and ranging (LiDAR) point clouds to accurately quantify urbanization effect

GIS for source water assessment and nonpoint source modeling in the Las Vegas Valley

This thesis develops a better understanding of issues related to surface water contamination and protection of drinking water sources in the Las Vegas Valley. A Geographic Information System (GIS) was used to identify source water protection zones and to estimate nonpoint source loads for the entire watershed; The extent of the source water protection zones is represented by the valley\u27s dry weather flows. After source water protection zones were defined, field work and GIS defined the potential contaminant sources and land uses within the protection zones; The GIS nonpoint source model shows that roads account for approximately 25% of the Total Nitrogen and 18% of the Total Phosphorus from nonpoint sources. Analysis suggest that a disproportionately high amount of nutrient loads have their origin within the source water protection zones. Approximately 10 to 7 percent of nutrient loads originate in the 5% of the total watershed area represented by protection zones

Land cover types of the Las Vegas Wash, Nevada

Vegetation type, extent, continuity, and structure are some of the most important factors that determine wildlife diversity and distribution. Other contributing factors that shape wildlife communities include disturbance, competition, climate, and water availability. Because vegetation communities in the southwestern U.S. gradate sharply along zones of soil moisture, wildlife are often restricted to specific vegetation types. Along the Las Vegas Wash (Wash), Nevada, more than 250 wildlife species have been documented to occur in distinct wetland, riparian, and upland vegetation types. Recent studies have investigated the diversity and distribution of amphibians, birds, fishes, mammals, and reptiles (Shanahan 2005, 2005a, Van Dooremolen 2005, O\u27Farrell and Shanahan 2006, Larkin 2006). Moreover, focused surveys for the endangered southwestern willow flycatcher (Empidonax traillii extimus) and Yuma clapper rail (Rallus longirostris yumanensis) have been conducted since as early as 1998 (SWCA 1998, 1999, 2000, 2001, 2002, 2003, 2005, 2006; McKernan and Braden 2001, 2002). Field surveys have concluded that wildlife habitats are improving. Habitat analyses are integral components of the biological surveys that are conducted in the Wash. Because survey locations are finite, however, vegetation descriptions are often spatially limited. Vegetative communities described from a landscape perspective are helpful to understand the landscape structure and its effects on the distribution and abundance of organisms. The Las Vegas Wash Coordination Committee, a multi-stakeholder collaborative planning group, has been facilitating biological resource inventories and ecological improvements along the Wash for the past several years. Besides the wildlife studies previously described, on the ground activities have included constructing multiple erosion control structures and stream bank protection facilities. Moreover, extensive revegetation projects have been completed to further protect the channel bed and banks from eroding as well as to improve wildlife habitat values. These activities are directed by a planning document that was completed in 2000, the Las Vegas Wash Comprehensive Adaptive Management Plan (CAMP). Among the action items that were listed in the CAMP was a recommendation to prepare a long-term wildlife management plan for the Wash, which is currently underway (Shanahan et al. 2007). In order for wildlife management planning to be successful, however, the availability and extent of wildlife habitats must be considered. Often, wildlife management is effectively accomplished by focusing management recommendations towards habitats. The goal for this study is to identify and delineate land cover types along the Wash with specific attention given to vegetated cover types (i.e., vegetation communities). Vegetation communities are described by using standardized vegetation classifications (Association for Biodiversity Information 2001), Geographic Information System (GIS) technologies, and appropriate ecological methodologies (e.g., Barbour et al. 1999, Mueller-Dombois and Ellenberg 1974). This study provides a critical catalog of vegetative communities along the Wash using a repeatable standardized nomenclature. This study was conducted to facilitate wildlife management planning along the Wash (Shanahan et al. 2007), however, ecosystem restoration initiatives (Kloeppel et al. 2006, Bickmore 2003) were intended to benefit from these data as well. Specifically important land cover classifications, such as wetlands, are also presented to help plan for and meet long-term management goals along the Wash

GIS-based evaluation of mid-block pedestrian crossing safety

Transportation related problems have become one of the most pressing and visible concerns of urban life. One major aspect of safety relates to pedestrian crossings, especially pedestrian crossings away from an intersection i.e. at mid-block locations. There is need to develop a program to address mid-block pedestrian crashes (MBPC) to better understand them. This thesis describes the development of set of tools designed to help better understand MBPCs. Included are general statistical methods, GIS database, and visualization interface software; This thesis evaluates the potential of spatial clustering techniques and nearest neighbor methods to identify areas where high concentrations of mid-block crashes are occurring. The methodology was tested and validated using a case study of mid-block locations in the Las Vegas metropolitan area. (Abstract shortened by UMI.)

Development of a safety analysis and an intersection infrastructure system

GIS and GPS technologies have found immense applications in the field of transportation engineering. Different features related to transportation safety are inventoried using these technologies. The databases so created serve as main source for safety analyses, decision making and reporting. Many different analyses tools are available to assist engineers, planners and policy makers in the process of improving transportation safety. GIS-based analyses tools provide tabular and graphic display, thereby expediting the analyses process and improving the spatial understanDing The advantages of such tools increase if they can be provided on the World Wide Web. One such software system that offers online analyses tool is the ArcIMS; This research is aimed at developing a GIS-based tool to inventory signalized intersection attributes. In addition, an internet based analyses system that utilizes the signalized intersection database and the crash database is developed. The tools provide number of choices to perform user-defined queries to generate specific results. The system is developed using Visual Basic .Net programming language. The applications developed here are demonstrated with the data available for the Las Vegas metropolitan area

The challenge of predicting flash floods from thunderstorm rainfall.

A major characteristic of the hydrometeorology of semi-arid regions is the occurrence of intense thunderstorms that develop very rapidly and cause severe flooding. In summer, monsoon air mass is often of subtropical origin and is characterized by convective instability. The existing observational network has major deficiencies for those regions in providing information that is important to run-off generation. Further, because of the complex interactions between the land surface and the atmosphere, mesoscale atmospheric models are currently able to reproduce only general features of the initiation and development of convective systems. In our research, several interrelated components including the use of satellite data to monitor precipitation, data assimilation of a mesoscale regional atmospheric model, modification of the land component of the mesoscale model to better represent the semi-arid region surface processes that control run-off generation, and the use of ensemble forecasting techniques to improve forecasts of precipitation and run-off potential are investigated. This presentation discusses our ongoing research in this area; preliminary results including an investigation related to the unprecedented flash floods that occurred across the Las Vegas valley (Nevada, USA) in July of 1999 are discussed

A Rural and Urban Study of the Food Environment in Select Nevada Geographies

National and county level examination of urban and rural food environments has taken place, but primary validation of venue existence and in-venue data are lacking. The literature show disparities in access to healthy foods through low density of large grocers/supermarkets, low variety and quality of produce and higher prices for a healthy diet in rural versus urban geographies. Rural areas are of unique concern due to poor health indicators such as higher obesity rates, higher diabetes rates, lower incomes and lower educations than urban residents. The goal of this study was to explore differences in the community and consumer level food environments between two Nevada geographies. Evidence was sought to test the hypotheses of venue density, the availability and quality of produce, and the price difference between standard and healthy items between rural and urban Nevada geographies. A cross-sectional study took place through direct quantitative and descriptive data collection in two rural Nevada counties and two urban census tracts in Las Vegas, NV. A Kruskal–Wallis, Mann–Whitney and a Bonferroni correction were performed on the quantitative store audit data to compare produce availability and quality scores, and the price differences between standard and healthy items between geographies. Primary data show a greater per-capita density of grocery and convenience venues in the rural area than the urban. A greater per-capita density of fast-food venues was found in the urban sample area. The variety and quality of produce in the rural grocer venues were lower than the urban supermarkets. No significant or functional price difference was found between the standard and healthier versions of select items within commonly purchased food groups, between rural and urban geographies

Imaging the mantle in southwestern, Utah using geochemistry, and geographic information systems

Basaltic volcanism is common in the transition zone from the Basin and Range to the Colorado Plateau. This study focuses on an 80 km long transect containing seven separate basalt fields spaced less than 20 km apart. The transect extends from eastern Nevada through northwestern Arizona and into southwestern Utah, across the crustal boundary defined as the transition zone; Geochemistry and geographic information systems (GIS) define the geometry and orientation of a mantle boundary trending approximately E-W, almost perpendicular to the crustal boundary. This study suggests that there is no genetic link between the mantle boundary and crustal boundary between the Colorado Plateau and the Basin and Range. This evidence supports the hypothesis that the mantle boundary may be an older more fundamental feature. Geochemical variability within each volcanic field is best explained by fractional crystallization. Field evidence, petrography, geochemistry and new dates support separate evolution of each volcanic field